Fuse wrench



Nov. 1, 1932; E. A. B-OHLMAN FUSE WRENCH Filed June 21, 1930 PatentedNov. 1, 1932 UNITED. STATE PATENT OFFICE v ERNEST A. BOHLMAN, OFCHICAGO, ILLINOIS, ASSIGNOR TO JEFFERSON ELECTRIC COMPANY, OF CHICAGO,ILLINOIS, A CORPORATION OF ILLINOIS FUSE WRENCH Application filed June21, 1930. Serial No. 462,731.

. The invention relates generally to wrenches and more particularly to awrench for assembling or disassembling ferrule-type renewable fuses.

.5 Some ferrule-type renewable fuses are made with end memberscomprising internally threaded metal caps covering the ends of thefuseto serve'as terminals therefor and which must be removed in order torenew the fuse. A. diametral slot is usually cut in the end face of thecap to receive a screw driver by which it may. be turned. It is usuallynecessary'to screw the caps tightly onto the fuse to afford properelectric contacts within thefuse, and, to remove a cap when it hasbeen'so screwed, considerable turning force is required to loosen it,especially after. the. fuse'has been blown.

j Other ferrule-type renewable fuses are made with metal sleeves orferrules fixed to the ends of the fuse and end-closing memberscomprising diametrically slotted plugs are threaded into the ends of thesleeves.

It is general practice to manufacture ferrule-type. fuses in two sizesfor a given voltage, namely, one size to accommodate from zero to thirtyamperes, and the other size from thirty-five to sixty amperes. Bothsizes are similar in form and differ only in .'.30 their dimensions.

The general object of the invention is to provide a novel wrench adaptedforuse on fuses of either of the above mentioned styles and with bothsizes thereof, which is light 23 and easy to handle although of veryrigid construction, and which is inexpensive to manufacture.

Otherobjects and advantages will become apparent from. the followingdescription taken in connection with the accompanying drawing, in which:

Figure 1 is a perspective view partially insection ofa wrenchembodyingthe features of the invention and showing a fuse having a cap about tobe placed in the wrench.

p 1 Fig. iis a perspective view of a fragmentary section taken at rightangles to the view shown in Fig. 1 and showing a fuse having a. threadedplug.

lVhile the invention is susceptible of various modifications andalternative constructions, I have shown in the drawing and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, but intend to cover '60 all modifications and alternativeconstrue tions falling within the spirit and scope of the invention asexpressed in the appended claims.

Ferrule-type' fuses of the two styles hereto- '65 fore'mentioned, onwhich a wrench embodying the features of the present invention may beused, are shown in Figs. 1 and 4respectively. The fuse shown in Fig. 1comprises a tube 10 on the respective ends of which are 10 threaded caps11. Each cap has a slot 12 extending diametrically across the'end faceof the cap and providing means by which the cap may be gripped to turnit.

The fuse shown in Fig. 4 comprises a tube 13 on the respective ends ofwhich are fixed sleeves or ferrules 14 which are internally threaded toreceive plugs 15, each plug having a slot 16 cut diametrically acrossits outer face. a It is to be'noted that the plug 15, and hence the slot16, lie within the limits of the sleeve 14 and that no slot is cut inthe end of the sleeve to match the slot in the plug.

It is essential that, in assembling a fuse, the cap or plug, as the casemay be, be screwed tightly onto the fuse to insure a proper relation ofparts within the fuse. Also when disassembling a fuse, it often is foundthat the cap or plug sticks, especially after the fuse has been blown,and that a considerable turning force is necessary to unscrew it. Theordinary screw driver is found not to be a very suitable tool forturning the cap or plug because of the inconvenience of holding the fusein axial alinement with the blade of the 9 screw driver to prevent theblade from tearing or marring the side of the slot and, hence, fromslipping out of the slot during turning. If, in the style of fuse havinga cap, the latter were to be grasped by a tool such as l pliers and thusturned, the pressure of such a tool necessary to hold the cap firmlywould cause the jaws of the tool to mar the surface of the cap and spoilthe contact thereof with the fuse clip.

The invention aims to provide a wrench whichmay readily engage the slotin the cap and hold the fuse in a centered position so that excessiveendwise ressure need not be exerted to maintain sucli engagement. It isalso constructed for use with either style of fuse and may be veryreadily handled.

The present embodiment, as shown in the drawing, comprises a rigidhollow body member 20 made of wood or other suitable material and havingits ends constructed for use respectively with the two different sizesof fuses of both styles. The external shape of the body member may besubstantially round with flattened sides so that it may be readilygrasped in the hand. The end of the wrench shown in Fig. 2 isconstructed for use with a' large size fuse such as a sixty-ampere fuse,while the end shown in Fig.3 is for a smaller size fuse such as athirty-ampere As the caps of both sizes of fuses are of similar shapeand differ only in their diinen'sions, the two ends of the wrench aresimilar differing only in certain dimensions, and only one end need bedescribed.

'Hle body member 20 is provided with an internal shoulder 21 spaced fromthe end thereof. A metal angle member extends across the inside of thebody member and has one I 22 resting against the shoulder while the 0':r leg constituting a blade 23 extends toward the end of the body member.A guide sleeve 24 constituting a socket and having a pair ofdiametrically opposite longitudinal slots is pressed into the end of thebody membe! with the slots fitting over the ends of the blade 23. Theperipheral surface of the sleeve 24 is roughened to hold it againstrotation relative to the body member and a pin 25 passes through boththe body member and the sleeve also to prevent such relative rotation.Thus, the blade 23 is secured against rotation relative to the bodymember.

In using the wrench on a fuse having a cap as shown in Fig. 1, the capis inserted into the guide sleeve 24 until the end face of the capstrikes the edge of the blade 23, and is then turned until the bladeenters the slot in the cap. By holding the fuse in one hand and thewrench in the other and exerting only a slight pressure, the wrenchfirmly grips the cap and the latter may then be turned. Since thecap isheld concentric with the body member-,'it is obvious that no greatendwise force need be exerted to prevent the blade from slipping out ofthe slot in the cap, even when a large turning force is exerted.

In order to be able to use the wrench on the style of fuse which has aplug threaded into the end thereof, as shown in Fig. 4, the blade 23 hasa pair of notches 26 in the respective ends thereof. When the fuse isinserted into the guide sleeve 24, the notches 26 provide spaces for theend of the sleeve 15 when the blade enters the slot 16 in the plug 15.

It is evident from the above thatI have provided a wrench which isadapted for use with either style of fuse. Being made chiefly of Wood,it is light although extremely rigid, and its shape is such that it isconvenient to use.

I claim as my invention 1. A wrench for turning threaded members on theends of ferrule-type fuses comprising, in combination, a hollow bodymember shaped to be readily grasped in the hand, a guide sleeve securedagainst rotation in the end of said body member and arranged to fiteasily over the end of the fuse, and a blade extending diametricallyacross and secured to the inner end of said sleeve and arranged to enterthe slot in the threaded member of the fuse when the end of the fuse isinserted in said sleeve.

2. A wrench for turning threaded members on the ends of ferrule-typefuses comprising, in combination, a hollow body member shaped to bereadily grasped in the hand and having an internal shoulder, a guidesleeve secured against rotation in the end of said body member andarranged to fit easily over the end of the fuse, said sleeve having apair of diametrically opposite longitudinal slots in its inner end, anda blade having its ends entering said slots and extending diametricallyacross said sleeve and in abutment with the internal shoulder of thebody member, said blade being arranged to enter the slot in the threadedmember when the fuse is inserted in the sleeve.

3. A wrench for turning threaded members on the ends of ferrule-typefuses comprising, in combination, a hollow body member shaped to bereadily grasped in the hand and having an internal shoulder, an anglemember mounted across the inside of the body member and having one leglying against said shoulder and the other leg constituting a bladeextending toward the end of the body member, a guide sleeve mountedwithin said end of the body member and having a pair of slots fittingover the ends of said last-mentioned leg to prevent relative rotationtherebetween, and means for. securing said sleeve against rotationrelative to said body member,

said blade being arranged to enter the slotinv the threaded member ofthe fuse when the end of the fuse is inserted in the guide sleeve.

4. A wrench for turning the plugs threaded in the ends of ferrule-typefuses comprising,

in combination, a hollow body member.

shaped to be readily grasped in the hand, a gulde sleeve secured withinthe end of said body member and arranged to fit easily over the end ofthe fuse, and a blade secured in a III diametrical position within saidbody mem-v ber and having a pair of notches adjacent its respective endsso that it may enter the slot in the plug of the fuse when the end ofthe fuse is inserted in the guide sleeve.

5. A Wrench for turning threaded members on the ends of ferrule-typefuses comprising, in combination, a body member of relatively softmaterial having a hole in one end, a metal guide sleeve pressed intosaid hole and having projections on its outer surface embedded in saidsoft material to hold said sleeve against rotation relative to saidmember, and a blade rigidly secured in said hole by said sleeve andarranged to enter the slot in the threaded member of the fuse when thelatter is inserted in said sleeve.

6. A Wrench for turning threaded members on the ends of ferrule-typefuses comprising, in combination, a body member having a hole in oneend, a guide sleeve having longitudinal ridges formed on its peripheryand pressed into said hole, said ridges cutting into said body member toprevent relative rotation therebetween, and a blade non rotatablysecuredin said hole by said sleeve and arranged to enter the slot in thethreaded member of the fuse When the latter is inserted in said sleeve.

In testimony whereof, I have hereunto af fixed my signature.

' ERNEST A. BOHLMAN.

